GIFTING MONEY TO CHILDREN

I WOULD LIKE TO LEAVE MY CHILDREN £25,000 EACH. THEY ARE FOUR AND TWO. I WOULD LIKE TO GIVE THIS MONEY TO THEM AS A CASH TRANSFER TO A UK BANK ACCOUNT - HOWEVER NEITHER OF THEM HAVE A BANK ACCOUNT YET. I AM AWARE THAT YOU MAY GIVE A TAX FREE GIFT WITHOUT TAX IMPLICATIONS TO ANYONE IN THE UK AS LONG AS YOU DON'T DIE WITHIN 7 YEARS. PROBLEM IS, £50,000 IS THE SUM TOTAL OF MY SAVINGS AND I AM VERY LIKELY TO DIE WITHIN THE NEXT FEW MONTHS. IDEALLY, I WOULD LIKE TO GIVE THEM THE MONEY INTO AN ISA ACCOUNT EACH WHICH WILL PAY COMPOUND INTEREST UNTIL THEY REACH THE AGE OF 18 WHEN THE ACCOUNT WILL BE THEIRS TO DO WHAT THEY WISH WITH. I HAVE NO DEBTS TO SPEAK OFF AND I AM SINGLE (DIVORCED) FROM THEIR MOTHER (MY EX WIFE)

ANY HELP MUCH APPRECIATED. THERE IS A LOT RIDING ON THIS QUESTION SO....